Unicode problems in C

[crazyfuturamanoob]

I want to be able to type faster, so I have used typespeed for practicing before. But I want to make a better typing program, with full unicode support.

I have piece of code to read key presses without waiting for carriage return (got the code from http://groups.google.com/group/comp.os.linux.development/browse_thread/thread/d3d0b4ff5a40dec7):


#include <termios.h>
#include <unistd.h>
#include <wchar.h>

...

static wchar_t get_key()
{
struct termios argin, argout;
wchar_t ch = 0;
tcgetattr( 0,&argin );
argout = argin;
argout.c_lflag &= ~(ICANON);
argout.c_iflag &= ~(ICRNL);
argout.c_oflag &= ~(OPOST);
argout.c_cc[VMIN] = 1;
argout.c_cc[VTIME] = 0;
tcsetattr( 0,TCSADRAIN,&argout );
read( 0, &ch, sizeof(ch) );
tcsetattr( 0,TCSADRAIN,&argin );
return ch;
}

(I don't usually copy-paste-modify code from the internet but I couldn't figure that out myself.)

I have a finnish keyboard, which has keys for ä and ö.

It's not possible to get ä nor ö with the function above (they show up as 뛃 and ꓃).

How to read unicode characters (without waiting for carriage return)?

[mmix]

slightly offtopic, try libutf from p9p

http://swtch.com/plan9port/unix/

[dwhitney67]

You should consider using getwchar() and putwchar(). As for controlling the input-blocking of standard-in, this should be done separately from the step to read input.

Try this app:


#include <stdio.h>
#include <termios.h>
#include <unistd.h>
#include <string.h>

// For yesOrNo, 1 is to enable non-blocking, 0 to disable (ie blocking).
int enableNonBlocking(int yesOrNo, int fileno)
{
static struct termios old;

if (yesOrNo)
{
struct termios tmp;

if (tcgetattr(fileno, &old))
{
return -1;
}

memcpy(&tmp, &old, sizeof(old));

tmp.c_lflag &= ~ICANON & ~ECHO;

if (tcsetattr(fileno, TCSANOW, (const struct termios*) &tmp))
{
return -1;
}
}
else
{
tcsetattr(fileno, TCSANOW, (const struct termios*) &old);
}

return 0;
}

// Main
//
#include <wchar.h>

int main()
{
enableNonBlocking(1, STDIN_FILENO);

printf("Enter a sentence ending with a .:\n");

wint_t ch = WEOF;

while ((ch = getwchar()) != '.')
{
putwchar(ch);
}
putwchar(ch);
puts("");

enableNonBlocking(0, STDIN_FILENO);

return 0;
}

[crazyfuturamanoob]

I solved it on my own:


int _get_key()
{
struct termios argin, argout;
int ch = 0;
tcgetattr( 0,&argin );
argout = argin;
argout.c_lflag &= ~(ICANON);
argout.c_iflag &= ~(ICRNL);
argout.c_oflag &= ~(OPOST);
argout.c_cc[VMIN] = 1;
argout.c_cc[VTIME] = 0;
tcsetattr( 0,TCSADRAIN,&argout );
read( 0, &ch, sizeof(ch) );
tcsetattr( 0,TCSADRAIN,&argin );
return ch;
}

wchar_t get_key()
{
char buf_src[16] = {0};
int x = _get_key();
memcpy( buf_src, &x, sizeof(x) );

wchar_t buf_dest[16] = {0};
mbstowcs( buf_dest, buf_src, 1 );

return buf_dest[0];
}

ä and ö work! :D:D:D

[dwhitney67]

That seems like a lot of code to read just one (wide) character. Consider simplifying it a bit before you consider yourself done with the task.

[crazyfuturamanoob]

I use my own "GUI" library, which allows reading and writing characters as if they were pixels. Edit: Your code works too so I use it. Thanks :)

I rewrote the function. Looks much more readable IMO:


int enable_non_blocking( int nonblocking, int fileno )
{
static struct termios old;
struct termios tmp;

if ( nonblocking )
{
if ( tcgetattr( fileno, &old ) )
return 0;

memcpy( &tmp, &old, sizeof(old) );
tmp.c_lflag &= ~ICANON & ~ECHO;

if ( tcsetattr( fileno, TCSANOW, (const struct termios*) &tmp ) )
return 0;
}
else
tcsetattr( fileno, TCSANOW, (const struct termios*) &old );

return 1;
}


Edit2: There is one problem: Pressing return will mess up terminal window. My GUI library doesn't work in non-blocking mode.
Edit3: And another problem. If the program segfaults, terminal will be in non-blocking mode and is completely unusable.

My solution doesn't look pretty but works better.